<?php
namespace Core\HttpClient;

/**
 * Adds Proxy support to the WordPress HTTP API.
 *
 * There are caveats to proxy support. It requires that defines be made in the wp-config.php file to
 * enable proxy support. There are also a few filters that plugins can hook into for some of the
 * constants.
 *
 * Please note that only BASIC authentication is supported by most transports.
 * cURL MAY support more methods (such as NTLM authentication) depending on your environment.
 *
 * The constants are as follows:
 * <ol>
 * <li>WP_PROXY_HOST - Enable proxy support and host for connecting.</li>
 * <li>WP_PROXY_PORT - Proxy port for connection. No default, must be defined.</li>
 * <li>WP_PROXY_USERNAME - Proxy username, if it requires authentication.</li>
 * <li>WP_PROXY_PASSWORD - Proxy password, if it requires authentication.</li>
 * <li>WP_PROXY_BYPASS_HOSTS - Will prevent the hosts in this list from going through the proxy.
 * You do not need to have localhost and the blog host in this list, because they will not be passed
 * through the proxy. The list should be presented in a comma separated list, wildcards using * are supported, eg. *.wordpress.org</li>
 * </ol>
 *
 * An example can be as seen below.
 * <code>
 * define('WP_PROXY_HOST', '192.168.84.101');
 * define('WP_PROXY_PORT', '8080');
 * define('WP_PROXY_BYPASS_HOSTS', 'localhost, www.example.com, *.wordpress.org');
 * </code>
 *
 * @link http://core.trac.wordpress.org/ticket/4011 Proxy support ticket in WordPress.
 * @link http://core.trac.wordpress.org/ticket/14636 Allow wildcard domains in WP_PROXY_BYPASS_HOSTS
 * @since 2.8
 */
class Proxy
{

    static $host;
    static $port;
    static $username;
    static $password;
    static $bypassHosts;

    /**
     * Whether proxy connection should be used.
     *
     * @since 2.8
     * @use WP_PROXY_HOST
     * @use WP_PROXY_PORT
     *
     * @return bool
     */
    public function is_enabled()
    {
        return isset(self::$host) && isset(self::$port);
    }

    /**
     * Whether authentication should be used.
     *
     * @since 2.8
     * @use WP_PROXY_USERNAME
     * @use WP_PROXY_PASSWORD
     *
     * @return bool
     */
    public function use_authentication()
    {
        return isset(self::$username) && isset(self::$password);
    }

    /**
     * Retrieve the host for the proxy server.
     *
     * @since 2.8
     *
     * @return string
     */
    public function host()
    {
        return self::$host;
    }

    /**
     * Retrieve the port for the proxy server.
     *
     * @since 2.8
     *
     * @return string
     */
    public function port()
    {
        return self::$port;
    }

    /**
     * Retrieve the username for proxy authentication.
     *
     * @since 2.8
     *
     * @return string
     */
    public function username()
    {
        return self::$username;
    }

    /**
     * Retrieve the password for proxy authentication.
     *
     * @since 2.8
     *
     * @return string
     */
    public function password()
    {
        return self::$password;
    }

    /**
     * Retrieve authentication string for proxy authentication.
     *
     * @since 2.8
     *
     * @return string
     */
    public function authentication()
    {
        return $this->username() . ':' . $this->password();
    }

    /**
     * Retrieve header string for proxy authentication.
     *
     * @since 2.8
     *
     * @return string
     */
    public function authentication_header()
    {
        return 'Proxy-Authorization: Basic ' . base64_encode($this->authentication());
    }

    /**
     * Whether URL should be sent through the proxy server.
     *
     * We want to keep localhost and the blog URL from being sent through the proxy server, because
     * some proxies can not handle this. We also have the constant available for defining other
     * hosts that won't be sent through the proxy.
     *
     * @uses WP_PROXY_BYPASS_HOSTS
     * @since 2.8.0
     *
     * @param string $uri URI to check.
     * @return bool True, to send through the proxy and false if, the proxy should not be used.
     */
    public function send_through_proxy($uri)
    {
        // parse_url() only handles http, https type URLs, and will emit E_WARNING on failure.
        // This will be displayed on blogs, which is not reasonable.
        $check = @parse_url($uri);

        // Malformed URL, can not process, but this could mean ssl, so let through anyway.
        if ($check === false) {
            return true;
        }

        if ($check['host'] == 'localhost' || isset($_SERVER['HTTP_HOST']) && $check['host'] == $_SERVER['HTTP_HOST']) {
            return false;
        }

        if (!isset(self::$bypassHosts)) {
            return true;
        }

        static $bypass_hosts;
        static $wildcard_regex = false;
        if (null == $bypass_hosts) {
            $bypass_hosts = preg_split('|,\s*|', self::$bypassHosts);

            if (false !== strpos(self::$bypassHosts, '*')) {
                $wildcard_regex = array();
                foreach ($bypass_hosts as $host) {
                    $wildcard_regex[] = str_replace('\*', '[\w.]+?', preg_quote($host, '/'));
                }

                $wildcard_regex = '/^(' . implode('|', $wildcard_regex) . ')$/i';
            }
        }

        if (!empty($wildcard_regex)) {
            return !preg_match($wildcard_regex, $check['host']);
        } else {
            return !in_array($check['host'], $bypass_hosts);
        }

    }
}
